Furan is an important intermediate for the production of many commercial products. In particular, furan can be easily hydrogenated to tetrahydrofuran, which is used in many industrial polymers.
Molybdenum-based catalysts have been widely used for the production of furan from butadiene. Vanadium, phosphorus and bismuth are known for use as co-catalysts or promoters. Catalysts that have been used previously include bismuth molybdates modifiable with sodium, silver or calcium and/or other metals (U.S. Pat. No. 4,322,358); silver molybdates modifiable with bismuth (U.S. Pat. No. 4,309,355); and molybendum/cobalt/phosphorus/oxygen compounds (U.S. Pat. No. 3,894,056).
Bismuth oxides modifiable with several elements including molybdenum have been used for the oxidative dehydrogenation of alkylaromatics and paraffins to produce olefinic unsaturated compounds (U.S. Pat. No. 5,780,700).
A need remains, however, for a catalyst that has a high selectivity to furan compounds in the oxidative dehydrogenation of unsaturated acyclic hydrocarbons, thereby obtaining increased yields of the desired furan compound as the reaction product.